1. Field of the Invention
This invention relates to improvements in Screw Tightening structure to tighten a bus bar and an end terminal of a connecting electric wire both of which constitute an internal circuit of a switch box.
2. Description of the Prior Art
Switch boxes such as a relay box or a fuse box have an internal circuit which is composed of a plurality of bus bars under normal conditions. End terminals of connecting electric wires for either electric supply or output are firmly tightened and fixed by screwing the bolts and the nuts on main bus bars.
FIGS. 4 and 5 show a conventional example of a screw tightening structure described above as disclosed in the Japanese Utility Model Application Laid Open No. 4-29165. Namely, a bolt 23 is fixed on one side of a case body 22 of a switch box 21 in such a way that the bolt 23 is integrally embedded in the case body 22 by insertion molding. Ends of a plurality of bus bars 24 and an end terminal (hereinafter called LA terminal) of the connecting electric wire 25 are fixed in such a manner that the ends and the LA terminal are securely tightened through a washer 27 by utilization of this stud bolt.
In the above both assembling and electric wiring for the switch box, the maker of the switch box has carried out the insertion molding of the bolt and distributing wires of the bus bars circuit, and the makers of automobiles have carried out the mounting of the LA terminal and tightening work of the nut, and as it did so, when the bolt is damaged because of excessive tightening of the nut, the only damaged portion can not be removed therefrom due to the insertion molding. For this reason, it must be substituted every wiring harness. Accordingly, this method resulted in the main cause of substantial cost.